1. Field of the Invention
This invention relates to wells pumped by reciprocating sucker rods and more particularly to shallow wells, principally water wells. Water well mechanics have ordinary skill in this art.
2. Description of Related Arts
Before this invention the applicant is unaware of sucker rod guides for water wells. Rod guides are known in the oil-well art. Oil wells are deeper than water wells. Usually, oil wells are at least 2,000 feet, and some over 10,000 feet. Water wells are normally shallow and when pumped, water wells with sucker rods are usually over 35 feet and seldom over 750 feet. Often windmills form the motor power for reciprocating sucker rods to pump water wells.
In recent years composite materials often referred to as fiber-reinforced plastics have been used for sucker rods.
Composite sucker rods are known in the oil well art and have many desirable qualities. However, composite rods tend to be more flexible than wooden or steel sucker rods. Therefore the composite rod is more likely to rub upon the surrounding eduction tube. Also, normally the composite material will result in greater wear than metal or wooden sucker rods, when they do rub.
Customarily oil wells use steel sucker rods, whereas water wells customarily use wooden sucker rods.
Before the use of composite sucker rods, rod guides were used with oil wells because of their great depth but were virtually unknown for water wells because of the shallow depth and the use of wood for sucker rod material.
Normally the oil well sucker rod guides are elongated about an axis and are fluted to form ribs or bars extending from the central body. The guides were sometimes molded upon the rod. (See OLINGER U.S. Pat. No. 5,115,863). Some of the guides had axial slots therein such as the EDWARDS ET AL U.S. Pat. Nos. 4,858,688 and 5,154,867 as well as OLINGER U.S. Pat. No. 5,115,863. Others had "snap on type openings" such as SABLE U.S. Pat. No. 4,575,163 and SABLE ET AL U.S. Pat. No. 5,191,938.
Also, some of the rod guides were mounted for movement upon the sucker rod such as OSTER Re.31,016. The OSTER Patent discloses an anti-friction surface having a short polish rod which is threaded on each end. The rod guide is loose upon the polished rod and telescopes over one end before the polished rod is threaded into a box fitting at either end.